Service Manual for WD10 Diesel Engine Expansion water tank Fig. 2-3 Expansion water tank 222 Check Engine Oil Level Check whether engine oil level is between the bottom scale and top scale on oil dipstick. Under no circumstances should the engine be started if the oil level is lower than the bottom scale (L) or higher than the top scale (H). Oil level checking should be done at least 5min later after engine stopped, in order to let engine oil have enough time to return to oil sump. Engine oil level difference between L and H: 3L Fig. 2-4 Oil dipstick 13